The biosphere is the part of the earths surface inhabited by living things. A biome is a huge eco-system and the world can be divided into nine major biomes. Each one has its own type of vegetation and wildlife and are divided by 4 main factors:
Temperature - this gradually decreases as you move away from the equator and increase the latitude. In the tropics the suns rays are very concentrated so there is dense vegetation in the tropics.
Precipitation - this happens in low pressure belts where air masses meet and air rises. Rainfall mainly occurs at the equator and at mid lattitudes all year round.
Sunshine - this determines the amount of light avaliable for photosynthesis
Humidity - this controls the rates of evaporation.
Altitude - temperatures decrease by 1*C for every 100 metres in height
Goods and Services:
The biosphere provides us with a range of goods and services.
The services include; regulating the composition of the atmosphere, maintaining the health of the soil, regulating water within the hydrological cycle, providing habitats for wildlife, provideing employment for locals and used for recreation.
The goods include; drinking water, meat, fish, fruit, nuts, biomass for energy, timber, fuelwood, rubber and medicines.
For indigenous people the biosphere provides everything they need and it also provides land for them to grow crops on. The land is only used for 5 years and then they move on to another plot to avoid the soil being exhausted.
The biosphere also provides many goods for commerical use however they tend to ruin the rainforest and many transnational companies exploit forest. They deforest the land to grow commercial plantations, to graze cattle, to search for ingredients for new medicines, to search for oils and much more.
Threats to the Biosphere:
There are many threats to the biosphere because of rapidly expanding population and economic development meaning people consume more food and fuel. These threats include:
Deforestation - commercial logging destroys forests meaning rainfall is not intercepted so forests flood causing soil erosion and so habitats are destroyed.
Pollution - water pollution destroys species which interupts food chains and therefore damages ecosystems
Toruism and recreation - high density mass tourism disturbs wildlife and habitats
Overharvesting - causes animals to be hunted to extinction so ruins food chains
Many species have become extinct due to natural events such as climate change and the destruction of the biosphere. Scientists believe increasing rates of this could lead to mass extinction. Humans impact this including; population growth, rising consumption of resources and human induced climate change.
Scientists believe half of all known species may become extinct due to climate change. Climate change may have many impacts on the biosphere including:
- habitiats will change and break up due to rising temperatures, changing rainfall patterns and rising sea levels
- extreme weather events will become more common such as droughts and floods
- species face extinction as they can't migrate to new habitats quickly enough
- pests and diseases will thrive in rising temperatures causing more extinction
Conserving The Biosphere:
National policies can be delivered in local areas, involving local people.
Goverments can set up protected areas which help to conserve, manage and restore biodiversity. Community forests have been established in the UK to provide new areas of trees near major cities.
Countries can get together to help develop wildlife conservation treaties for example the RAMSAR convention of conserving wetlands and CITIES the convention on international trade in endangered species. These international treaties are very difficult to manage as there are so many conflcting interests.
Sustainable management of ecosystems is a mid way between total protection of ecosystems and total exploitation where there is no protection. It involves:
- conserving the ecosystem for future generations by ensuring that it isn't used faster than it can be renewed. Zoning can be used to do this.
- local people so the ecosystem provides them with resources
- schemes which train and educate locals and involve them in the decisions
- allowing local people to make a living from ecotourism
- being environmentally freindly. It avoids practices like destroying the forest, trees are left to protect watershed, only adult fish are caught and harvest is selective with only large trees logged.